Conservation Problems in the Vatican Necropolis

European Journal of Science and Theology, April 2018, Vol.14, No.2, 131-140 _______________________________________________________________________ CONSERVATION PROBLEMS IN THE VATICAN NECROPOLIS Daniela Gallo1*, Pietro Zander2 and Claudia Pelosi3 1 University of Tuscia, Department of linguistic and literary, historical, philosophical and legal studies (DISTU), Largo dell’Università, 01100 Viterbo, Italy 2 Fabbrica di San Pietro, Vatican City 3 University of Tuscia, Department of Economics, Engineering, Society and Business Organization, Largo dell’Università, 01100, Viterbo, Italy (Received 25 September 2017, revised 20 October 2017) Abstract The Vatican Necropolis represents one of the most surprising sites during a visit to the monumental complex of Saint Peter’s Basilica. This case study is an important example of conservative challenges in hypogeum environment where a lot of degradation phenomena affect materials and structures. For this reason, various professionals were called to intervene and to work in a spirit of positive and reciprocal collaboration for guaranteeing the preservation and fruition of both religious and archaeological areas on short and long term without causing further damages. It was possible to begin the delicate restoration according to a plan that, for the first time, considered the necropolis in its entirety. Each individual solution adopted for the rehabilitation of the necropolis was carefully evaluated on the basis of the needs expressed by different specialists, placing every intervention organically within the master plan. Keywords: hypogeum, conservation issues, procedures, storage, microclimate 1. Introduction The Vatican Necropolis is located under the level of the Crypt of Saint Peter, underneath the central aisle of the homonymous Basilica [1, 2]. Indeed, it has been recognized like a site doubly underground [2, 3]. The Necropolis area was originally at ground level on the Vatican hill, the fourteenth region of Rome divided by the Imperator Augusto. According to literary sources the area was extremely unhealthy and marshy. “The historian Martial [2 – Epigrams, 10, 45, 5 and 6, 92, 3] reports that they are produced very poor quality wine that tasted like vinegar and sometimes resembled poison.” Successively the Imperator Caligula (37-41 AD) began the construction of a circus (Figure 1) that was to be improved by Claudius (41-54 AD) and completed by Nero (54-68 AD). At the centre of the track there was an obelisk over 33 metres high [4, 5]. It remained in its original location for more than 15 *E-mail: [email protected] Gallo et al/European Journal of Science and Theology 14 (2018), 2, 131-140 centuries and in 1586 it was moved by the architect Domenico Fontana (1543- 1607) to its present position in front of Saint Peter basilica [6]. This exceptional operation, required by the Pope Sixtus V (1585-1590), called for 907 men, 40 winches and 75 horses. Figure 1. View of the Vatican Circus, engraving of Carlo Fontana [5] (from [2, p. 6], ©Fabbrica di San Pietro). The circus fell into disuse as early as the second century AD, when the area was occupied by a number of graves and monumental tombs of various types and sizes, in accordance with the oldest Roman laws that prohibited the burial of the dead inside the city walls (Figure 2). Most of them were pagan, but Christian burials were also found, especially from the age of the Constantine basilica (Figure 3). The Necropolis was used until the fourth century, when Constantine decided to level the ground and covered the entire area with soil to build the first Saint Peter’s church; according to very ancient Roman custom and law the inviolability of tombs was strictly protected. It was an incredibly vast undertaking that involved the shifting of more than forty thousand cubic metres of soil. In the process of burial, it was necessary to level the parts of the tombs that protruded above the established level of the floor of the new church. The Constantine building was destroyed in 1500, and a bigger and more beautiful Basilica was constructed. The Vatican necropolis remained buried for 1600 years. 132 Conservation problems in the Vatican Necropolis Figure 2. Plan of the Vatican Necropolis showing in different colours the restoration dates of mausoleums (from [3, p. 110], ©Fabbrica di San Pietro). Figure 3. Reconstruction of Mausoleums Z-Psi ([7], ©Fabbrica di San Pietro). Systematic excavation of the Necropolis began only during the pontificate of Pius XII (1939-1958). On the occasion of the works aimed to reset the floor of Saint Peter’s Crypt in January 18th, 1941, the workers discovered, at a depth of one and half metres, the elegant cornice of a structure, subsequently labelled Mausoleum F (the mausoleum of Caetennius Antigonus). In earlier centuries, a sense of religious respect and reverential awe, as well as the wish to not disturb the tombs of the popes, martyrs and of a multitude of unknown Christians, prevented any excavations under the floor of the old basilica. Archival documents and direct evidences between 16th and 17th century provide us only summary information about some occasional discoveries made in the area of the necropolis on the occasion of works carried out in Saint Peter Basilica. During the construction of the new basilica a lot of marble sarcophagi were found. Most sarcophagi came from the 4th century basilica and they were described by Antonio Bosio in Roma Sotterranea published in Rome in 1632. Those accidental discoveries never led to more thorough research [2]. 133 Gallo et al/European Journal of Science and Theology 14 (2018), 2, 131-140 Considerable technical difficulties, often unforeseen, were encountered during the excavations. For example, it became necessary to open passages in the foundations of the old and the new basilica, to deviate and ensure the correct drainage of the underground water, to strengthen and lay the foundations for the pillars of the church above the necropolis. The church, without the Constantine filling, would have been suspended in the air. A series of elegant burial structures, lying adjacent to one another and running from west to east along an axis diverging slightly from that of the Church above, was discovered during the excavations. The 22 structures, revealed during the papacy of Pius XII, constitute only a small part of a larger monumental complex that probably extends until the river Tevere (Figure 1). 2. Conservative problems To the first archaeologists, the necropolis appeared just as Constantine had seen it, preserved on Earth for centuries. Once the rubble added by Constantine was removed, the archaeologists discovered brick walls, stucco and mosaic decorations, inscriptions, cinerary urns, sarcophagi and splendid frescoes of the mausoleums that had preserved their original colours unaltered for one thousand and six hundred years. After many centuries, the soil offered men an archaeological site that had remained practically intact and untouched. Figure 4. Vatican Necropolis, Mausoleum M, interior north wall with the Christian figure of the fisherman before and after restoration (from [3, p. 113], ©Fabbrica di San Pietro). Soluble salts are clearly visible before restoration. At the end of the first phase of archaeological research in 1950, the unavoidable problems linked to underground excavation sites emerged. These problems were mainly related to unstable micro-climatic conditions and microbiological diffusion. Increasing values of temperature and relative humidity, linked to high levels of carbon dioxide and uncontrolled air currents, 134 Conservation problems in the Vatican Necropolis caused evident and progressive deterioration patterns. The degradation phenomena were visible on the surfaces through the formations of salt (chlorides, sulphates and nitrates, Figures 4 and 5), algae and microorganisms which over time developed so covering walls and pictorial decorations [8-11]. Increasing number of visitors over time (Figure 6) also contributed to the gradual deterioration, as they brought in spores and bacteria, causing harmful micro-climactic variations. Figure 5. Vatican Necropolis, Mausoleum N, exterior south wall before and during the cleaning operation (from [3, p. 116], ©Fabbrica di San Pietro). Figure 6. Number of visitors from 1970 to 2008 (from [3, p. 111], ©Fabbrica di San Pietro). 135 Gallo et al/European Journal of Science and Theology 14 (2018), 2, 131-140 With regard to the necropolis’ problems, immediately attempts to remedy them were tried by performing a series of interventions mainly planned according to urgency criteria. Above and beyond a general plan for understanding the entire excavation area, starting from 1998, the Fabric of St. Peter’s arranged to embark upon a well-constructed program of works. The starting point of the working approach was based on the idea that the necropolis needed to be treated as a ‘patient’ to be cured. 3. Operational goals On the base of the above defined approach, before starting the restoration activities, it was decided to acquire a deeper and more precise understanding of the Vatican Necropolis through examination of the existing materials and documentation, and the subsequent cataloguing and direct verification of the gathered data. Information was collected by examination the vast bibliography, archival and iconographic documentation and graphic survey of the structures, all for the knowledge of the ‘patient’. Photographic documentation was performed by using Hasselblad cameras and lenses (40 mm,

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